Spare tire thoughts?

I felt dumb when I discovered my truck didn't come with a spare. There's a well for storing it, but no spare.

Since I have to buy one, any thoughts on which wheel I should get? Rivian won't sell me one. I just bought a matching Pirelli tire, but would love a suggestion as to a cheap wheel that would do the job.

The fact that Rivian doesn't make this easy is disappointing. They refuse to tell me what sort of wheel they recommend!

Thanks.